The present invention relates to a cable tray or cable raceway comprised of several elongate, generally U or C shaped sections which are clamped end to end to produce the cable raceway. Where some of the cable or wiring is required external to the raceway for connection to a wiring device at a particular location, typically either holes are field drilled into the side of the raceway or knockouts are provided as part of the manufacturing process and can be removed. A conduit bushing is put into each hole through which the cable exits the raceway. Use of bushings causes a tight or small radius turn in the cable, which could possibly damage it.
As an alternative to merely drilling holes, it is known to install a cable raceway cable exit box either directly in the raceway or sometimes to one lateral side of the raceway. A usually narrow, often tubular opening is provided between the raceway and the exit box, which has the above mentioned drawback of forming a tight turn in the cable. Further, the exit box for the cable raceway may sometimes be deep, front to back of the raceway, in order to house a wiring device to which some of the cables in the raceway would be attached. Examples of such wiring devices include various switches, plug sockets, electric components, illumination devices connected to optical fiber cables, any power or communications device, etc. In order to house a cable exit box, which is deep in order to contain a deep wiring device, and especially where the exit box is installed in the raceway, a deeper than normal raceway is needed to house the deep box. This is undesirable because extra material is required for the raceway which makes it more expensive, and the cable raceway greater depth may make it more difficult to conceal in a wall, ceiling, or the like.
U.S. Pat. No. 4,338,484 teaches a first wire channel with an adjacent second wire channel disposed along one side, with gaps in the abutting sides of the two channels through which a wire may pass. The additional channel is not an exit box adapted to receive any wiring device, and the depth of the additional channel is substantially that of the first channel, since support of a wiring device in either channel is not contemplated.
U.S. Pat. No. 5,403,974 shows access from a cable channel to a wiring device. It does not suggest a cable exit box adapted for supporting a wiring device therein and at the raceway section.
U.S. Pat. No. 3,725,568 shows a conventional cable exit from a cable raceway. See also U.S. Pat. Nos. 3,131,512 and 2,023,433 to similar effect.